You may reveal any land card with either or both of the appropriate subtypes. It doesn’t have to be a basic land. For example, you could reveal Prairie Stream from the Battle for Zendikar set to satisfy the ability of Fortified Village.

4/8/2016

Lands don’t have a subtype just because they can produce mana of the corresponding color. Fortified Village itself is neither a Forest nor a Plains, even though it produces green and white mana, so you can’t reveal one to satisfy the ability of another.

4/8/2016

If a Forest or Plains is entering the battlefield from your hand at the same time as Fortified Village, you may reveal the other land to have Fortified Village enter untapped.

4/8/2016

If an effect instructs you to put Fortified Village onto the battlefield tapped, it will still enter the battlefield tapped even if you reveal a land card from your hand.